Money lands in your business account. Split it before you spend it: tax, profit, and what the business runs on.
It is simple percentage math. Whatever lands in the account gets split three ways, in a fixed order: tax first, profit second, and the business runs on what is left. That order is the point. Most founders spend first and hope there is something left for tax. This flips it.
Where the idea comes from. This is the Profit First method, from the book of the same name by Mike Michalowicz. The book uses more accounts and a set of target percentages. Three accounts is enough to start.
How to use it with your bank. Most online business banks let you create sub-accounts for free. Name them Operating, Tax and Profit. Every time money lands, move the tax and profit amounts by hand, or set up an automatic rule if your bank has one.
Not tax advice. The percentage you set aside for tax depends on your income, your state and how your LLC is taxed. This tool only does the arithmetic. Your CPA gives you the number.
Need the official place to file your LLC? The State Filing Finder. Working on your numbers? The Margin Napkin and The Three Buckets.